There have been a couple of recent posts asking about dosage so it's worth reading this guidance.
https://thebms.org.uk/wp-content/uploads/2021/10/14-BMS-TfC-Progestogens-and-endometrial-protection-01H.pdf
It's 9 pages, but the first page covers quite a lot.
The most relevant part for some women is the dose of Utrogestan when using it vaginally. This has to be the same as orally, (not half as some women were being advised by some drs, based on very limited evidence.)
Stute et al. 2016 reported a systematic review on the impact of micronised progesterone on the endometrium. The authors suggested that estrogens with sequential micronised progesterone (4% corresponding to 45 mg/day for 10 days per month) or intermittent (100 mg every other day) for up to 3–5 years may be safe (off-label use). The authors acknowledged that there was lack of sufficient data regarding optimal vaginal administration within HRT to guide practice.18
More evidence in adequately powered studies is required to assess the optimal dose and duration of vaginal progesterone intake to provide optimal endometrial protection within HRT regimens. Based on current evidence if progesterone was considered for vaginal administration (out of license use) in women who experience side effects with oral intake, this should ordinarily be given in similar doses and durations as suggested for oral progesterone intake with HRT.